共查询到20条相似文献,搜索用时 265 毫秒
1.
考虑能量利用的完善性(Yong效率)和合理性(能级匹配),提出了Yong经济系数的表达式,并把其作为制冷方案选择的依据,对三种制冷方案进行了Yong经济性的计算比较,其结论与只考虑经济性或只考虑Yong效率时得出的结论截然不同,而这一结论更符合节能的目的。 相似文献
2.
煤炭一直以来都是中国最主要的一次性能源,相应地,燃煤锅炉也占有电力市场绝大部分份额。燃煤锅炉存在诸多能量损失途径,能量转换效率较低。系统地分析燃煤锅炉的热力性能非常必要。是热力学第二定律中的一个重要概念,它不仅能反映能量的数量,更能反映能量的品质。基于概念,对某600MW超临界燃煤锅炉模型进行了详细的分析,综合考虑物理和化学,计算了系统的损失、耗散等参数,对锅炉的设计、优化提供了可靠依据。 相似文献
3.
4.
利用分析法对太阳能喷射制冷系统进行分析,了解系统各部件的损分布情况,并分析其原因,给出了系统总损随喷射系数变化的规律和喷射制冷循环各部件的损百分比随喷射系数变化的规律,为优化系统提供依据。分析结果表明:太阳能喷射制冷系统中,太阳能集热器的损最大,其次是冷凝器和喷射器;提高喷射器的喷射系数对于降低系统损、提高系统效率至关重要。 相似文献
5.
根据热经济性指标和的物理意义,定义锅炉效率、机组效率、发电煤耗率的数学计算式;由小扰动理论和微分理论,当抽汽压损变化时,在热力系统汽水分布方程的基础上详细推导抽汽量变化与不同类型加热器出口水焓与疏水焓的微分关系式;根据锅炉效率、机组效率、发电煤耗率的数学计算式,推导锅炉效率、机组效率、发电煤耗率变化与抽汽量的微分关系式。结合N1000-25/600/600机组,定量分析抽汽压损变化对锅炉效率、机组效率、发电煤耗率的影响,为有效分析机组经济性提供理论依据。 相似文献
6.
7.
在某汽轮机除湿级的空心静叶上设计了不同的热蒸汽喷射缝,应用两相均质混合模型和湿蒸汽平衡相变模型,对具有缝隙的叶栅流场进行了全三维定常的数值计算。引入参数的方法进行能量转化过程的经济性评估。结果表明:尾缘喷射热蒸汽时,同一喷射流量下,缝隙宽度越大,有效效率越高。同时,在较大缝隙宽度下,有一个最佳的喷射流量,此时的有效效率最高。压力面中部喷射热蒸汽时,在喷射流量比小于6%下,各方案的有效效率均比无热蒸汽喷射的原型要高。同一喷射流量下,顺主流喷射且缝隙宽度越大,其有效效率越高。 相似文献
8.
根据分析理论,把锅炉、汽轮机及发电厂热力系统作为一个整体,通过对发电厂各环节进行分析找到具体损失环节并对具体位置提出改造方案,是发电厂改造的一种新方法。以某超超临界机组为例,运用分析理论找到损失环节,找到二次风温及给水温度对锅炉系统及电厂热力系统影响的关系,通过增加一级高压加热器提高给水温度,同时在保证锅炉排烟温度不变的前提下适当地提高二次风温,分析在给水温度及二次风温的双重作用下,锅炉乃至整个机组性能的变化。结果表明,当给水温度由299.5℃升高至322℃时,二次风温由327.8℃升高至360℃,锅炉系统传热损失由3 443 kJ/kg降低至3 254 kJ/kg,燃烧环节损失由6 204 kJ/kg降低至6 158 kJ/kg,锅炉效率由54.15%升高至54.45%,机组目的效率由42%升高至46.7%。 相似文献
9.
采用平衡分析法,分别对小型热电联产系统和分散锅炉房供热系统进行了流分析,把两者计算所得效率作一对比,从而得出热电联产系统是取代分散锅炉房供热的节能措施之一。同时还对热电联产系统内各环节中的流损失进行计算,得出各热力设备的效率,找出系统用能不合理的主要薄弱环节,为今后设备的工艺过程改进指出了方向。 相似文献
10.
11.
天然气热、电、冷三联供的热经济性分析 总被引:11,自引:0,他引:11
提出系统Yong经济系数方法,对天然气热、电、冷三联供系统,天然气发电系统和天然气热电联供系统进行分析,计算出三系统的Yong经济系数,对其进行比较分析,指出天然气热、电、冷三联供系统具有较高的热经济性。进一步对天然气价格进行灵敏度分析,得出三系统在不同天然气价格下的Yong经济系数。图4表8参5 相似文献
12.
以300MW机组煤粉炉省煤器为例,对锅炉常压空气燃烧、常压富氧燃烧和5种不同增压(6MPa)富氧燃烧方案下的锅炉对流受热面尺寸、烟气流量、烟气侧传热系数和压降等参数进行了计算和分析,根据基于经济性分析的单位换热量换热器总费用最小的原则确定省煤器的最佳设计结构.结果表明:与常压空气燃烧相比,常压富氧燃烧下烟气体积流量减小了28.5%,对流传热系数减小了11.5%;增压富氧燃烧下的烟气体积流量减小了98.82%,随着烟气流速的增大,受热面面积减小,烟气侧传热系数和压降增大;最佳方案中的烟气流速为1.54m/s时,单位换热量换热器总费用约为常压空气燃烧下的60%,烟气侧压降为582.65Pa,烟道截面积仅为常压空气燃烧下的7.8%. 相似文献
13.
Wu Shuangying Li Yourong Thermal Engineering College of Chongqing University Chongqing China 《热科学学报(英文版)》2001,10(3):218-222
honductiOnHeat exchangee as one of the thennal equlpment,is widely used in energy systems, the imPrvement ofheat exchangers perfonnance is imPOrtan for savingenergy and twving tbe efficiency, so it is necessaryto emPloy a general driterion to evaluate heatexchanger perfrmance. In the design of heatexchangers, numrous perfrmance evaluation criteriaealst tO heIP to detennine their fhatUfs11]. Thesecriteria lead towards the goal of oPtindzationprocedurs. They dePend on the asPeCt of o~zation… 相似文献
14.
小型太阳能热泵地板供暖系统的优化研究 总被引:1,自引:1,他引:0
建立了太阳能热泵地板供暖系统的能量分析、可用能分析数学模型,模拟了上海供暖期的气候条件,给出了系统各部件的可用能损失情况。着重从太阳能集热器并联的组数出发对系统进行了优化研究,并给出了系统供暖性能系数和可用能效率,为该系统的设计及应用提供参考。 相似文献
15.
Utilizing renewable energy (RE) is an important part of the design and development of green buildings. However, it is unreasonable to assess renewable energy utilization (REU) only with the net ratio of end-use energy provided by the renewable energy system to a building's total energy consumption, but ignoring the system efficiency of REU with the necessary extra conventional energy consumption, such as electricity. In this paper, the energy quality coefficient (EQC) is introduced to describe the quality of energy, while the energy conversion coefficient (ECC) is applied to evaluate energy system efficiency. The indexes and their expressions were developed based on exergy analysis. Based on these two indexes, an effective substitution ratio (ESR) was developed for the evaluation of REU. Furthermore, the ESR of utilizing RE to substitute for single type and multiple types of conventional energy is discussed. Finally, case studies were conducted and some conclusions were drawn from the results for application of RE in buildings. 相似文献
16.
《International Journal of Hydrogen Energy》2022,47(62):26067-26081
In this present research study a multi-generation energy system which is coupled with CO2 capture unit which is based on Rankine cycle, organic Rankine cycle, ejector cooling system and absorption chiller has been analyzed via energy, exergy, exergy-economic aspects by developing MATLAB, also to achieve the optimum operating condition genetic algorithm has been applied for system optimization. The objective of this study is to propose an optimized efficient integrated energy system to recycle the energy waste of a typical industrial factory. The optimization has been illustrated on a Pareto frontier to achieve the optimum scheme of the multi-generation system regarding technical and economic viewpoints. Results indicate the optimal condition of this system has occurred at 0.37 exergy efficiency with 0.03 $/s. Furthermore, by surging the mass flow rate of waste gases up to 70 kg/s, net power output augmented up to 7500 kW. Besides, hydrogen production and produced desalinated water rise up to 8.5 g/s and 16 kg/s, respectively. 相似文献
17.
Exergy analysis of the energy use in Greece 总被引:1,自引:0,他引:1
In this work, an analysis is being done on the concept of energy and exergy utilization and an application to the residential and industrial sector of Greece. The energy and exergy flows over the period from 1990 to 2004 were taken into consideration. This period was chosen based on the data reliability. The energy and exergy efficiencies are calculated for the residential and industrial sectors and compared to the findings of a previous study concerning the exergy efficiency of the Greek transport sector. The residential energy and exergy efficiencies for the year 2003 were 22.36% and 20.92%, respectively, whereas the industrial energy and exergy efficiencies for the same year were 53.72% and 51.34%, respectively. The analysis of energy and exergy utilization determines the efficiency of the economy as a whole. The results can play an important role in the establishment of efficiency standards of the energy use in various economy sectors. These standards could be utilized by energy policy makers. 相似文献
18.
19.
20.
基于热力学第一定律,反映热泵能量数量关系的性能指标-供热系数,在用于评价热泵系统节能效益及对热泵系统进行可行性评价的问题上,存在一定的局限性。本文对这一问题进行了分析。在此基础上,根据热力学第二定律,提出了以热泵系统单位火用损供热率作为其性能评价指标的思想。以此作为热泵系统的性能评价指标,更科学、更客观。 相似文献